The inter-governmental agency has been ratified by 19 countries and has 46 signatories to its framework agreement.
France has welcomed ISA's feat of acquiring the status as an international organisation.
"I welcome the achievement today by the International Solar Alliance of status as an international organization," Minister for Europe and Foreign Affairs Jean-Yves Le Drian said in a statement.
ISA's goal is to facilitate the large-scale deployment of solar energy in the 121 countries in the area between the tropics by aggregating the demand for funding, technology and innovation.
The countries, which are part of this alliance, have exposure to the sun for over 300 days in a year. (ANI)